thumb|Nautilus under way
thumb|right|Nautilus, as pictured in [[The Mysterious Island]]
Nautilus is the fictional submarine belonging to Captain Nemo featured in Jules Verne's novels Twenty Thousand Leagues Under the Seas (1870) and The Mysterious Island (1875).
Description
Nautilus is described by Verne as "a masterpiece containing masterpieces". It is designed and commanded by Captain Nemo. Electricity provided by sodium/mercury electric batteries (with the sodium provided by extraction from seawater) is the craft's primary power source for propulsion and other services. The energy needed to extract the sodium is provided by coal mined from the sea floor.
Nautilus is double-hulled, and is further separated into water-tight compartments. Its top speed is . In Captain Nemo's own words: